Many kinds of photographic cameras are known, in which the shutter tensioning or cocking mechanism is coupled or interconnected with the film feeding mechanism, so that a single movement of a single member (usually a manually operable lever on the top or bottom of the camera) serves both to tension or cock the shutter and to feed the film, advancing it through the distance of one frame. In most of these known cameras, the mechanism automatically prevents a double exposure, because a fresh exposure cannot be made until the shutter has been cocked or tensioned, and the more act of tensioning the shutter serves to advance the film.
However, there are circumstances when a photographer may purposely wish to make a double exposure. Some cameras have provision for this, allowing the shutter to be tensioned for another exposure without advancing the film. But the mechanism to accomplish this is usually complicated and expensive, and liable to get out of order.
An object of the present invention is the provision of mechanism which, in a normal or basic mode of operation, will advance the film simultaneously with tensioning the shutter, and which, when desired, can be shifted so that the shutter may be tensioned independently of any feeding movement of the film, and at the same time to accomplish this by the use of mechanism which is comparatively simple, inexpensive, sturdy in use, and not to get out of order.
Another object is the provision of such mechanism in which there is a gearing connection between a shutter tensioning member and a film winding member, and in which such gearing connection can be operatively disconnected when desired, in a comparatively simple manner.
Still another object is the provision of such disconnectable gearing or coupling means so designed and constructed that the means for disconnecting it serves the double purpose of disconnecting the gearing to allow the making of a double exposure, and disconnecting it to allow the rewinding of the exposed film onto the original supply spool.
A further object is the provision of such mechanism so designed that the film take-up spool is firmly clamped in a non-rotatable position when the gearing is disconnected for the purpose of making a double exposure, but is not clamped and is free to rotate when the gearing is disconnected for the purpose of rewinding the film onto the supply spool.
A still further object is the provision of such disconnectable mechanism so designed that after the making of one double exposure, the gearing is automatically reconnected to its normal operating condition, to prevent the accidental making of a second double exposure, although permitting the gearing to be again purposely disconnected to permit another exposure on the same film frame, if desired.